Electric fan

ABSTRACT

An electric fan includes a motor unit, a pair of opposite fan units, a bracket, a stand, and a rotation-enabling mechanism. The motor unit includes a motor having two opposite output shafts, and a motor casing surrounding the motor and having a bottom side that has two opposite end portions. The fan units are coupled respectively to and driven by the output shafts. The bracket has two opposite securing portions respectively secured to the end portions of the bottom side of the motor casing, and a supporting shaft connected to and disposed between the securing portions. The stand is pivotally connected to the supporting shaft. The rotation-enabling mechanism includes a driving unit mounted on the bracket, and a linkage connected pivotally to the stand and driven by the driving unit.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority of Taiwanese application no. 093141118,filed on Dec. 29, 2004.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The invention relates to an electric fan, more particularly to anelectric fan with a pair of fan units, a motor with a motor casing, anda bracket secured to two opposite end portions of the motor casing.

SUMMARY OF THE INVENTION

The object of the present invention is to provide an electric fan havinga pair of fan units driven by a motor that is supported by a bracketwhich is capable of minimizing vibration of the electric fan during use.

Accordingly, an electric fan of this invention comprises a motor unit, apair of opposite fan units, a bracket, a stand, and a rotation-enablingmechanism.

The motor unit includes a motor having two opposite output shafts, and amotor casing surrounding the motor casing and having a bottom side thathas two opposite end portions.

The fan units are coupled respectively to and driven by the outputshafts.

The bracket is disposed below the motor unit, and has two oppositesecuring portions that are respectively secured to the end portions ofthe motor casing, and a supporting shaft that is connected to and thatis disposed between the securing portions of the bracket.

The stand is pivotally connected to the supporting shaft.

The rotation-enabling mechanism includes a driving unit that is mountedon the bracket, and a linkage that is connected pivotally to the standand that is connected to and driven by the driving unit so as to berotatable together with the bracket and the motor unit relative to thestand.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features and advantages of the present invention will becomeapparent in the following detailed description of the preferredembodiments with reference to the accompanying drawings, of which:

FIG. 1 is an assembled fragmentary partly sectional view of the firstpreferred embodiment of an electric fan according to the presentinvention;

FIG. 2 is an assembled fragmentary partly sectional view of the secondpreferred embodiment of an electric fan according to the presentinvention; and

FIG. 3 is an assembled fragmentary partly sectional view of the thirdpreferred embodiment of an electric fan according to the presentinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Before the present invention is described in greater detail withreference to the accompanying preferred embodiments, it should be notedherein that like elements are denoted by the same reference numeralsthroughout the disclosure.

Referring to FIG. 1, the first preferred embodiment of an electric fan100 according to the present invention is shown to include a motor unit10, a pair of opposite fan units 20, a bracket 30, a stand 40, and arotation-enabling mechanism.

The motor unit 10 includes a motor 12 having two opposite output shafts13, and a motor casing 11 surrounding the motor 12 and having a bottomside 16 that has two opposite end portions 161. A pair of protrusions 15protrude respectively from the end portions 161 of the bottom side 16 ofthe motor casing 11.

The fan units 20 are coupled respectively to and driven by the outputshafts 13.

The bracket 30 is disposed below the motor unit 10, and has two oppositesecuring portions 311 that are respectively secured to the end portions161 of the bottom side 16 of the motor casing 11, and a supporting shaft32 that is connected to and that is disposed between the securingportions 311. In this embodiment, the bracket 30 includes a top plate 31that has two opposite end portions which define respectively thesecuring portions 311 of the bracket 30, and a middle portion 312 thatis disposed between the end portions of the top plate 31. The supportingshaft 32 extends downwardly from the middle portion 312 of the top plate31. The bracket 30 further includes an L-shaped plate 34 that has avertical portion 341 extending downwardly from one of the end portionsof the top plate 31, and a horizontal portion 342 extending from thevertical portion 341 and cooperating with the vertical portion 341 todefine a recess 343 therebetween. The securing portions 311 of thebracket 30 are respectively secured to the protrusions 15 on the bottomside 16 of the motor casing 11 through fastening screws 33.

The stand 40 is formed with a stand hole 41 that receives the supportingshaft 32 therein. The stand 40 is thus pivotally connected to thesupporting shaft 32.

The rotation-enabling mechanism includes a driving unit 50 having acontroller 51 mounted on the horizontal portion 342 of the L-shapedplate 34 within the recess 343, and a linkage 53 that is connectedpivotally to the stand 40 through a bolt 42 and that is connected to anddriven by the driving unit 50. The driving unit 50 further includes acam 52 that is connected pivotally to the linkage 53 so as to drive thelinkage 53 together with the bracket 30 and the motor unit 10 to rotaterelative to the stand 40. The controller 51 normally includes a motorand a speed-reduction gear set (not shown in the drawing). Since thecomponents of the controller 51 and the operation the rotation-enablingmechanism are well known to those skilled in the art, they will not bedetailed further for the sake of brevity.

During assembly, the top plate 31 is first fixedly mounted on the bottomside 16 of the motor casing 11 through engagement of the securingportions 311 of the bracket 30 and the end portions 161 of the bottomside 16 of the motor casing 11. Next, the rotation-enabling mechanism 50is mounted on the L-shaped plate 34. Then, the L-shaped plate 34 ismounted to a lateral side of one of the end portions of the top plate31. In operation, when the motor 12 is started for driving the fan units20, and when the fan units 20 rotate relative to the stand 40, avibration force generated thereby will be distributed uniformly over thebracket 30.

Referring to FIG. 2, the second preferred embodiment of this inventionis similar to the first preferred embodiment, except that the bracket 30includes a U-shaped portion 312 that is disposed between and that isconnected to the securing portions 311 of the bracket 30, and that theL-shaped plate 34 is mounted on a lateral side of the U-shaped portion312.

Referring to FIG. 3, the third preferred embodiment of this invention issimilar to the first preferred embodiment, except that the bracket 30includes a U-shaped portion 34 having two opposite ends connectedrespectively to the securing portions 311 of the bracket 30, anddefining a recess 343 therein. The supporting shaft 32 extendsdownwardly from the U-shaped portion 34, and the driving unit 50 ismounted in the recess 343 in the U-shaped portion 34 of the bracket 30.

By virtue of the bracket 30, vibration resulting from rotation of thefan units 20 and the motor unit 10 can be reduced.

While the present invention has been described in connection with whatis considered the most practical and preferred embodiments, it isunderstood that this invention is not limited to the disclosedembodiment but is intended to cover various arrangements included withinthe spirit and scope of the broadest interpretation so as to encompassall such modifications and equivalent arrangements.

1. An electric fan comprising: a motor unit including a motor having twoopposite output shafts, and a motor casing surrounding said motor andhaving a bottom side that has two opposite end portions; a pair ofopposite fan units coupled respectively to and driven by said outputshafts; a bracket disposed below said motor unit and having two oppositesecuring portions that are respectively secured to said end portions ofsaid motor casing, and a supporting shaft that is connected to and thatis disposed between said securing portions; a stand pivotally connectedto said supporting shaft; and a rotation-enabling mechanism including adriving unit that is mounted on said bracket, and a linkage that isconnected pivotally to said stand and that is connected to and driven bysaid driving unit so as to be rotatable together with said bracket andsaid motor unit relative to said stand.
 2. The electric fan as claimedin claim 1, wherein said bracket includes a top plate that has twoopposite end portions which define respectively said securing portionsof said bracket, and a middle portion that is disposed between said endportions of said top plate, said supporting shaft extending downwardlyfrom said middle portion of said top plate, said bracket furtherincluding an L-shaped plate that has a vertical portion extendingdownwardly from one of said end portions of said top plate, and ahorizontal portion extending from said vertical portion and cooperatingwith said vertical portion to define a recess therebetween, said drivingunit being mounted in said recess.
 3. The electric fan as claimed inclaim 2, wherein said driving unit includes a controller that is mountedon said horizontal portion of said L-shaped plate and that is receivedin said recess, and a cam that is connected pivotally to said linkage.4. The electric fan as claimed in claim 1, wherein said bracket furtherhas a U-shaped portion that is disposed between and that is connected tosaid securing portions of said bracket, said supporting shaft extendingdownwardly from said U-shaped portion of said bracket, said bracketfurther including an L-shaped plate that has a vertical portion securedto said U-shaped portion, and a horizontal portion extending from saidvertical portion and cooperating with said vertical portion to define arecess therebetween, said driving unit being mounted on said horizontalportion within said recess.
 5. The electric fan as claimed in claim 1,wherein said bracket further has a U-shaped portion having two oppositeends which are respectively connected to said securing portions of saidbracket, and defining a recess therein, said supporting shaft extendingdownwardly from said U-shaped portion of said bracket, said driving unitbeing mounted in said recess in said U-shaped portion.
 6. The electricfan as claimed in claim 1, wherein said motor casing is formed with apair of protrusions that protrude respectively from said end portions ofsaid bottom side of said motor casing, said securing portions of saidbracket being respectively secured to said protrusions.
 7. The electricfan as claimed in claim 6, further comprising fastening screws forsecuring said securing portions of said bracket to said protrusions onsaid end portions of said bottom side of said motor casing.